Recent activity

The geomagnetic field was quiet to active on December 26. Solar wind
speed ranged between 389 and 557 km/sec. A strong coronal stream began to dominate the solar wind after 15h UTC and early on
Dec.27 solar wind speed has increased further to near 700 km/sec. The interplanetary magnetic field has at times been strongly
southwards.

Solar flare activity was low. Solar flux was 127.4 (slightly enhanced by a long duration B level enhancement caused by an
erupting filament at the northeast limb. 123.1 was the
value obtained at 18h UTC - this is the lowest measured solar flux since the first days of August, 2001), the planetary A
index was 15 (STAR Ap - based on the mean of three hour ap indices: 16.1).
Three hour interval K indices: 22244434 (planetary), 12233434 (Boulder).

The background x-ray flux is at the class B3 level.

At midnight there were 3 spotted regions on the visible disk. A total of 3 C class events were recorded during the day. A C1.9
flare at 08:35 UTC apparently had its source just behind the southwest limb, probably in old region 10224.

Region 10229 decayed and became spotless early in the day.
Region 10230 added a few small spots while the main penumbra was mostly unchanged. Flares: C1.0
at 01:08 and C1.4 at 02:01 UTC.
Region 10231 did not not change much and remained mostly quiet.
Region 10234 was quiet and stable.
Region 10235 decayed and was spotless by early afternoon.

Coronal holes

A large and well defined trans equatorial coronal hole was in a geoeffective position on December 24-25.

Processed SOHO EIT 284 image at 01:06 UTC on December 27. Any black areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be active to minor storm on December 27 with a chance of an isolated major storm interval.
Unsettled to active is likely on December 28-29 due to a coronal stream. Long distance medium wave (AM) band propagation along
east-west paths over high and upper middle latitudes is very poor.

Coronal holes (1)

Coronal mass ejections (2)

M and X class flares (3)

1) Effects from a coronal hole could reach Earth within the
next 5 days.
2) Material from a CME is likely to impact Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48
hours.

Data for all numbered solar regions according to the Solar Region Summary provided by SEC/NOAA. Comments are my own, as is the
STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SEC or where SEC has observed no spots.

Solar region

Date numbered

SEC
spot
count

STAR
spot
count

Location at midnight

Area

Classification

Comment

10229

2002.12.14

1

N27W90

0010

AXX

became spotless
early in the day

10230

2002.12.17

3

4

S07W63

0120

CAO

classification was HSX
at midnight

10231

2002.12.19

3

3

S24W77

0110

CSO

area was near 0050
at midnight

10232

2002.12.21

N13W73

plage

10233

2002.12.23

N13E01

plage

10234

2002.12.24

2

3

N17E45

0060

CAO

10235

2002.12.25

3

N14E15

0010

BXO

now spotless

Total spot count:

12

10

SSN:

62

40

Monthly solar cycle data

Month

Average solar
flux at Earth

International sunspot number

Smoothed sunspot number

2000.04

184.2

125.5

120.8
cycle 23 sunspot max.

2000.07

202.3

170.1

119.8

2001.11

210.6

106.5

115.5 (+1.5)

2001.12

235.1

132.2

114.6 (-0.9)

2002.01

226.6

114.1

113.5 (-1.1)

2002.02

205.0

107.4

114.7 (+1.2)

2002.03

179.5

98.4

113.4 (-1.3)

2002.04

189.8

120.7

110.5 (-2.9)

2002.05

178.4

120.8

108.8 (-1.7)

2002.06

148.7

88.3

(106.4 predicted, -2.4)

2002.07

173.5

99.9

(102.8 predicted, -3.6)

2002.08

183.6

116.4

(99.6 predicted, -3.2)

2002.09

175.8

109.3

(96.6 predicted, -3.0)

2002.10

167.0

97.5

(93.1 predicted, -3.5)

2002.11

168.7

95.0

(87.8 predicted, -5.3)

2002.12

165.2 (1)

135.8 (2)

(83.5 predicted, -4.3)

1) Running average based on the daily 20:00 UT observed solar flux value at 2800
MHz.
2) Unofficial, accumulated value based on the Boulder (SEC/NOAA) sunspot number. The official
international sunspot number is typically 25-45% less.

This report has been prepared by Jan
Alvestad. It is based partly on my own observations and interpretations, and
partly on data from sources noted in solar
links. Comments and suggestions are always welcome.